acid-catalyzed asymmetricBaylis-Hillmanreaction is described. Good to high enantioselectivities were obtained using 3 mol % chiral catalyst. Novel camphor-derived dimerized ligands were prepared from the condensation of (+)-ketopinic acid with the corresponding diamines and hydrazine under acidic conditions. When alpha-naphthyl acrylate was used as a Michael acceptor, the reaction is complete within
Chiral chelating agents and chiral catalysts, which are formed from the chiral chelating agents and metal, are described. One chiral chelating agent has a general formula (1) as illustrated below:
1
wherein R represents H, methyl, ethyl, a primary, secondary or tertiary straight, branched or cyclic alkyl group having 3-7 carbon atoms, a heterocyclic or aromatic group, an aromatic group substituted at the 2-, 3- or 4-position, an aromatic-like group, or a naphthyl or naphthyl-derived group, and n is an integer between 0 and 4.
Complementary chemistry! α‐Isocupreine (α‐ICPN) was synthesized for the first time in one step fromquinine by treatment with CF3SO3H (see scheme). This compound serves as an enantiocomplementarycatalyst to β‐isocupreidine (β‐ICD) in the Morita–Baylis–Hillman reaction.
互补化学!通过CF 3 SO 3 H处理,从奎宁一步一步合成了α-异cupreine(α-ICPN)(参见方案)。在Morita-Baylis-Hillman反应中,该化合物可作为β-异cupreidine(β-ICD)的对映体互补催化剂。
Enantioselective Synthesis of the Optically Active α-Methylene-β-hydroxy Esters, Equivalent Compounds to Morita−Baylis−Hillman Adducts, Using Successive Asymmetric Aldol Reaction and Oxidative Deselenization
作者:Isamu Shiina、Yu-suke Yamai、Takahisa Shimazaki
DOI:10.1021/jo051276y
日期:2005.9.1
The asymmetricaldol reaction of a tetra-substituted ketene silyl acetal including an alkylseleno group with aldehydes has been developed by the promotion of Sn(OTf)2 coordinated with a chiral diamine to afford the corresponding aldols having chiral quaternary centers at the α-positions. The facile oxidative deselenization of these aldol compounds produces optically active α-methylene-β-hydroxy esters
Design and synthesis of bistereogenic chiral ionic liquids and their use as solvents for asymmetric Baylis–Hillman reactions
作者:Satish Garre、Erica Parker、Bukuo Ni、Allan D. Headley
DOI:10.1039/b808502a
日期:——
containing two chiral centers in the side chain bonded to the 2-position of the imidazolium cation and different anions have been synthesized, characterized and used as chiral solvents for asymmetricBaylis-Hillman (BH) reactions; good yields and fair enantioselectivities were obtained.